1. Field of the Invention
The present invention relates to a light source device and an endoscope device that automatically adjust light quantity of illumination light using a diaphragm member.
2. Description of the Related Art
Generally, light source devices used in endoscope devices or the like have a diaphragm unit that adjusts light quantity of illumination light supplied from a light source to irradiate a subject so that luminance of light forming an image on a photo acceptance element such as a charge coupled device (CCD) is to be substantially constant.
As means for adjusting the light quantity of the illumination light, for example, Japanese Unexamined Patent Application Publication No. 2000-241718 discloses a light source device that has a diaphragm member on an optical path of illumination light emitted from a light source, and an opening/closing amount of the diaphragm member is controlled so that the luminance becomes substantially constant. That is, the light source device disclosed in the document, in controlling the opening/closing amount of the diaphragm member, compares a light quantity adjustment signal generated by a light quantity adjustment signal generation circuit based on a luminance signal received by a CCD with reference voltage of brightness appropriate for observation. Then, the opening/closing amount of the diaphragm member is adjusted based on the error signal, and the light quantity is automatically adjusted so that the level of the light quantity adjustment signal corresponds to the reference voltage.